Use of a single particle intra-cavity laser particle spectrometer for measurements of HEPA filters and filter systems
Current tests of HEPA filters and/or filter installations using DOP aerosols and conventional forward light-scatter photometers are limited to measuring protection factors of 10/sup 4/ to 10/sup 5/. In addition, forward light-scattering photometers have markedly decreased sensitivity to less than 0.3 ..mu..m particles and basically measure only a scattering signal which is not uniquely related to any given concentration or size distribution of scatterers. These limitations require that high efficiency systems, such as multiple stage HEPA filters, be evaluated one stage at a time, a procedure which is quite often impractical for many existing air cleaning systems and which may be in error. In order to obviate these difficulties, a single particle intracavity laser particle spectrometer has been used to measure protection factors of up to 2.4 x 10/sup 8/ for multiple HEPA systems and individual double ply HEPA filters. Because of the instrumental size resolution, protection factor as a function of particle size can be determined from .06 ..mu..m to 2.9 ..mu..m. The lack of background enables single counts to be statistically significant. Since coincidence errors occur at particle concentration greater than 10/sup 6//liter, a known dilution must be introduced to measure challenge concentrations greater than this. The dilution measurement may be accomplished with the aid of a forward light-scattering photometer.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 7156366
- Report Number(s):
- LA-UR-76-1537; CONF-760822-12; TRN: 08-019585
- Resource Relation:
- Conference: 14. US ERDA air cleaning conference, Sun Valley, ID, USA, 2 Aug 1976
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
AEROSOLS
AIR FILTERS
AIR CLEANING SYSTEMS
ENVIRONMENTAL ENGINEERING
PERFORMANCE TESTING
EFFICIENCY
FEASIBILITY STUDIES
PARTICLE SIZE
PHOTOMETERS
COLLOIDS
DISPERSIONS
ENGINEERED SAFETY SYSTEMS
ENGINEERING
EQUIPMENT
FILTERS
MEASURING INSTRUMENTS
POLLUTION CONTROL EQUIPMENT
SIZE
SOLS
TESTING
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)
420202 - Engineering- Protective Structures & Equipment